Power operated sanding machine

ABSTRACT

A hand-manipulated sanding machine with a base plate on which is secured a backing pad for a sandpaper sheet. The base plate is carried on the machine housing by a plurality of one-piece mounting posts which are elastically deformable and detachably connected to the base plate by a bayonet-like connection. Sandpaper holders are pivotally mounted directly on base plate bearing portions and are biased into position by leaf springs.

United States Patent [191 Thomas et al.

[ 51 Nov. 26, 1974 POWER OPERATED SANDING MACHINE Inventors: Robert A.Thomas, Shreveport, La;

Jerry Wayne Sellers, Lexington; Roger Wayne Morley, Medina, both ofTenn.

Rockwell International Corporation, Pittsburgh, Pa.

Filed: Feb. 26, 1973 Appl. No.: 335,929

[73] Assignee:

US. Cl. 51/170 MT Int. Cl 1324b 23/04, B24b 23/08 Field of Search 51/170MT, 170 TL, 382,

References Cited UNITED STATES PATENTS 12/1956 Roods 51/170 MT 2,885,8335/1959 Neff 51/170 MT 3,336,702 8/1967 Endersi... 51/170 MT 3,345,78410/1967 Stelljesm. 51/170 MT 3,543,449 12/1970 Scott 51/170 MT 3,747,2807/1973 Stroezel 51/170 MT Primary Examiner-Donald G. Kelly [57] ABSTRACT14 Claims, 21 Drawing Figures Q a 40 i 54 64 52 5o n F 68 46 52 I ll r 1I, l I i 92 l PATENTEL, M26 1974 SHEEH 2 BF 5 PATENTL 31172 81974 SHEEF3 OF 5 PATENTE; .QGVZSISM 3, 9,9

SHEET u UF 5 FIG. 9

FIG. I0

PATENT E HJV 2 61974 SHEEF 5 [IF 5 FIG. I

POWER OPERATED SANDING MACHINE FIELD OF INVENTION This invention relatesto power operated sanding machines and particularly to the portable typeof sanding machines in which a motor driven pad assembly is suspendedfrom the motor-receiving housing.

BACKGROUND Conventional power operated, portable sanders typicallycomprise a housing for receiving a drive motor and a pad assembly driveconnected to the motor and suspended from the housing by fourelastically deformable posts. The elastically deformable posts aredeflectible to permit orbital or oscillating motion of the pad assemblyrelative to the motor-receiving housing. The pad assembly provides abacking for a sheet of sandpaper or abrading paper which is held inplace by clamps on the pad assembly.

Examples of prior sanding machines are described in U.S. Pat. No.3,345,784 issued to C. R. Stelljes et al on Oct. 10, 1967 for OrbitalFinishing Sander, U.S. Pat. No. 3,267,622 to L. Frostad on Augf23, 1966for Abrasive Pad Structure For Portable Sanding Machine, U.S. Pat. No.3,546,822 issued to A. A. Hutchins on Dec. 15, 1970 for Clip For SurfaceTreating Tool, U.S. Pat. No. 3,336,702 issued to S. G. Enders on Aug.22, 1967 for Oscillating Platen For Abrading Tool, U.S. Pat. No.2,606,947 issued to R. Happe on Aug. 12, 1952 for Electric Motor ForSanding Tools Or The Like, U.S. Pat. No. 3,543,449 issued to W. H. Scottet al on Dec. 1, 1970 for Dual Motion Surface-Dressing Machine, U.S.Pat. No. 2,697,897 issued to D. l. Dickinson on Dec. 28, 1954 forRubbing Machine, U.S. Pat. No. 2,893,174 issued to 1. Jepson on July 7,1959 for Surface Treating Machine, U.S. Pat. No. 2,848,850 issued to B.G. Metoff on Aug. 26, 1958 for Electric Sanders, U.S. Pat. No. 3,555,743issued to W. L. Geiger on Jan. 19, 1971 for Power Sander, U.S. Pat. No.2,885,833 issued to G. M. Neff on May 12, 1959 for Hand Held Sanding andAbrading Machine, U.S. Pat. No. 3,418,761 issued to M. I. Sheps on Dec.31, 1968 for Dual-Action Power Operated Abrading Tool, U.S. Pat. No.3,375,616 issued to W. H. Scott et al on Apr. 2, 1968 for Dual MotionSurface-Dressing Machine, U.S. Pat. No. 3,199,251 issued to S. G. Enderson Aug. 10, 1965 for Driving Mechanism For Abrading Tool, U.S. Pat. No.2,697,898 issued to R. T. Osman on Dec. 28, 1954 for Recurrent MotionAbrading Apparatus, U.S. Pat. No. 2,969,656 issued to S. G. Reuter onJan. 31, 1961 for Coupling Device, U.S. Pat. No. 3,396,963 issued to A.A. Hutchins on Aug. 13, 1968 for Resilient Cushion Structure, U.S. Pat.No. 3,224,149 issued to E. M. Harrington et al on Dec. 21, 1965 for HandSander, U.S. Pat. No. 2,441,506 issued to R. T. Osman on May 1 1, 1948for Recurrent Motion Abrader, U.S. Pat. No. 2,509,561 issued to A. J.Dremel on May 30, 1950 for Clip For Holding Sanding Paper, U.S. Pat. No.2,749,679 issued to N. T. Anton on June 12, 1956 for Shoes For RubbingDevices, and U.S. Pat. No. 2,764,852 issued to A. N. Emmons on Oct. 2,1956 for Portable Power Operated Sanding Machine.

SUMMARY AND OBJECTS OF INVENTION As compared with the structuresdescribed in the foregoing patents, the present invention provides for anovel and simplified structure for suspending or supporting thepad-carrying base plate from the motor housing.

In the sanding machine of this invention, the posts for supporting thebase plate are formed at their lower ends with coupling flanges that areadapted to be received and locked in sockets in the base plate. Theupper ends of each pair of posts are integrally joined together by aspacer portion to define a one-piece mounting member that is formed fromelastically deformable material. By torsionally deflecting the posts orflexing the spacer portions, or both, the coupling flanges are rotatableabout the longitudinal axes of their posts to positions where they maybe insertable into the sockets in the base plate. After the couplingflanges are seated in base plate sockets, the one-piece elasticallydeformable mounting member is relaxed to turn the coupling posts tolocking positions where they engage portions of the base plate tothereby detachably couple the posts to the base plate for supporting thebase plate from the posts.

With the foregoing summary in. mind, a major object of this invention isto provide a novel construction for supporting the base plate from thehousing of the sanding machine.

Another and more specific object of this invention is to provide a novelstructure for coupling the base platesupporting posts to the base plate.

According to another feature of this invention, the motor housing islongitudinally divided into a pair of separately formed shells havinginwardly opening cavities that receive the spacer portions of each ofthe previously mentioned one-piece, dual-post mounting members. Thespacer portions are trapped between the shells and are held in placeonly by separable seating surface engagement with the cavity-definingsurfaces of the shells to thereby secure the upper ends of the baseplate'supporting posts to the housing.

Thus, another object of this'invention is to provide a novelconstruction for securing the upper ends of the base plate-supportingposts to the housing.

Another and more specific object of this invention is to provide a novelsanding machine in which a plurality of mounting members for supportingthe base plate are trapped between the shells of the longitudinallydivided housing and are held in place only by separable seating surfaceengagement with interior surfaces of the shells.

From the foregoing it will be appreciated that the sanding machine ofthis invention requires no screws or other fasteners for securing thebase plate-mounting posts to either the base plate or to the motorhousing. The novel construction of this invention furthermore providesfor the easy, simplified and quick assembly and disassembly of theposts.

According to still another feature of this invention, a novel clampingstructure for securing sandpaper or the like to the pad assemblyeliminates the need for a pivot pin. Heretofore, pivot pins supported onthe base plate were utilized to pivotally mount the sandpaper clamps formovement between clamping and unclamping positions. According to thisinvention specially constructed clamps or paper holders are pivotallymounted directly on integral bearing portions of the base plate toeliminate the need for pivot pins or the like.

Thus, another object of this invention is to provide a novelconstruction for clamping; or holding sheets of sandpaper or otherabrading paper on the pad assembly.

These and other objects of this invention will appear as the descriptionproceeds in connection with the appended claims and below-describeddrawings.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a poweroperated, hand sanding machine incorporating the principles of thisinvention;

FIG. 2 is a fragmentary side elevation showing the sander of FIG. 1 withone of the halves of the longitudinally split housing removed toillustrate internal parts of the sanding machine;

FIG. 3 is an interior side elevation of the right-hand half of the splithousing shown in FIG. 1;

FIG. 4 is an interior side elevation of the left-hand half of the splithousing shown in FIG. 1;

FIG. 5 is a plan view of one of the dual post mounting members shown inFIG. 2;

FIG. 6 is a front elevation of the mounting member shown in FIG. 5;

FIG. 7 is a side elevation of the mounting member shown in FIG. 5;

FIG. 8 is a fragmentary, perspective, partially exploded'view of themounting member of FIG. 5 and the pad assembly;

FIG. 8A is a bottom plan view of the mounting member shown in FIG. 5;

FIGS. 9, 10, 11 and 12 are sections taken respectively along the lines99, 10-10, 1111 and 12-12 of FIG. 2;

FIG. 13 is a section taken substantially along lines 13--13 of FIG. 2;

FIG. 14 is a view similar to FIG. 8, but showing one of the mountingposts torsionally deflected for inserting the locking flange on thebottom of the post into the flange-receiving socket in the base plate;

FIG. 15 is a rear elevation of the forward paper holder shown in FIG. 1;

FIG. 16 is a top plan view of the paper holder shown in FIG. 15;

FIG. 17 is a side elevation of the paper shown in FIG. 15;

FIGS. 18 and 19 are sections respectively taken substantially alonglines 18-18 and l919 of FIG. 13; and

FIG. 20 is a view similar to FIG. 18, but showing the paper holderpivoted to a position where it is disengageable from the base plate.

DETAILED DESCRIPTION Referring now to the drawings and more particularlyto FIGS. 1 and 2, the portable hand manipulatible, power driven sandingand abrading machine incorporating the principles of this invention isshown to comprise a hollow, longitudinally split, clam shell typehousing or casing 20. Housing 20, as shown in FIG. 2, contains anelectric motor 22 and an eccentric drive mechanism 23. Mechanism 23drive connects motor 22 to a pad assembly 24 for imparting an orbitalmotion to pad assembly 24.

Pad assembly 24 comprises a rigid, rectangular backing shoe or baseplate 25 and a resilient, flat-sided pad 26 of felt, elasticallydeformable yieldable material or the like. Pad 26 is fixed, as bybonding, to the underside of base plate 25. Pad assembly 24 is supportedbelow or on the underside of housing 20 and is horizontal when thesander is held in such a position that the rotational axis of motor 22is vertical.

Pad assembly 24 provides a backing for a sheet of sandpaper indicated at28 in FIG. 2. The motion of pad assembly 24 resulting from energizationof motor 22 is in a plane that is substantially normal to the rotationalaxis of motor 22.

Motor 22 may be of any conventional, suitable construction and, as shownin FIG. 2, comprises a stator 30 having field windings peripherallysurrounding an armature 32. Armature 32 is mounted on an armature shaft34 which extends coaxially through stator 30 and which is driveconnected by mechanism 23 to to pad assembly 24 in a manner to beexplained in greater detail later on.

With continued reference to FIGS. 1 and 2, housing 20 has a hollow bodyportion 38, a grip type handle 40 extending rearwardly from body portion38, and a grippable knob portion 41 extending forwardly from bodyportion 38. Motor 22 and mechanism 23 are received in body portion 38.Handle 40 houses an electrical on-off switch 42 having a manuallymanipulatable switch actuator or trigger 44 for controlling operation ofmotor 22. Power is supplied to operate motor 22 through a conventionalpower cord 46 having conductors conventionally connected to switch 42and motor 22 for supplying current under the control of switch 42.

As shown in FIG. 2, a commutator 50, forming a part of motor 22, iscarried by shaft 34 and is electrically connected to armature 32 in theusual manner. Brush elements 52, which are spring biased into electricalcontact with the commutator periphery, are mounted in electricallynon-conductive brush holders 54.

Pad assembly 24 is supported on the underside of body portion 38 whichopens downwardly from the position of the machine as shown in FIG. 2.

As shown in FIGS. 1, 3 and 4, housing 20 is longitudinally divided intotwo complementary shells and 62 to provide a clam shell type enclosurefor the internal parts of the sander. Shells 60 and 62 are separatelymolded from a suitable electrically non-conductive plastic and haveoppositely dished curvatures.

Shells 60 and 62 are respectively formed with mating longitudinal edgesurfaces indicated at 64. Edge surfaces 64 seat against each other alonga substantially planar interface that longitudinally and mediallyintersects body portion 38, handle 40, knob 41 and pad assembly 24. Therotational axis of shaft 34 lies substantially in a plane containingthis interface. Machine screws 68 (see FIG. 2) extending through boresin shell 62 are threaded into tapped bores in shells 60 to firmly andrigidly secure shells 60 and 62 together.

Bearings 82 and 83 respectively journel the outboard and inboard ends ofarmature shaft 34. Stator 30, bearings 82 and 83, and brush holders 54are all seated in mating, generally complementary cavities that areformed in shells 60 and 62 and that are generally indicated at 84 inFIGS. 3 and 4. There motor parts, namely the stator, the armature shaftbearings and the brush holders are all trapped in position betweenshells 60 and 62 and are confined only by separable seating surfaceengagement with the interior cavity defining surfaces of shells 60 and62.

A fan 92 is fixed on shaft 34 axially between armature 32 and bearing83. Rotation of fan 92 draws air in through openings 93 at the top ofhousing 20, causing the air to flow through and cool motor 22. Theheated air is exhausted through openings 93a which are also formedthrough housing 20. The hub of fan 92 is axially confined between thedownwardly directed face of armature 32 and an annular spacer 94.

Mechanism 23, which may be of any suitable conventional construction,may correspond to the construction described in US. Pat. No. 3,345,784.As shown in FIG. 2, mechanism 23 comprises a flexible coupling 99 and aneccentric 100 having a hub portion 102 that is journalled in a rollerbearing 104. A bore 108, which is formed through hub portion 102, iseccentric to the outer cylindrical periphery of hub portion 102 whichengages and is coaxial with the inner race of bearing 104. Bearing 104is coaxially seated in an upwardly opening cylindrically contouredsocket 110 which is integrally formed in base plate 25.

Coupling 99 may be the same as that described in US. Pat. No. 3,345,784and comprises an elastically deformable flexible member 120 and a pairof threaded stud members 122 and 124 that are interconnected by flexiblemember 120. Member 122 is threaded into the lower end of shaft 34, andmember 124 is threaded into bore 108.

From the foregoing construction of mechanism 23, it will be appreciatedthat mechanism 23 will cause pad assembly 24 to orbit about the axis ofshaft 34 upon energization of motor 22.

In accordance with one feature of this invention, pad assembly 24 issecured to housing only by a pair of specially constructed, elasticallydeformable, one-piece members 150 and 151 to permit orbital, oscillatoryor reciprocatory displacement of pad assembly 24 relative to housing 20.Members 150 and 151 may be formed,

as by molding, from any suitable, yieldable, elastically deformable orelastomeric material such as rubber. Members 150 and 151 suspend padassembly 24 from housing 20 as shown.

Referring to FIGS. 5-8, member 150 comprises a pair of spaced apart,solid cylindrical posts 154 and 156 and a flat-sided spacer or bridgingportion 158 that integrally joins the upper ends of posts 154 and 156together. When spacer portion 158 is straight as shown in FIGS. 58,posts 154 and 156 are in coextensive, parallel spaced apart relationwith each other. Spacer portion 158 bridges the space between posts 154and 156 and is sufficiently thin to allow it to be easily flexed andtwisted in the region between posts 154 and 156.

As shown in FIGS. 6, 8 and 8A, post 154 terminates in a coupling foot orflange 160 of generally rectangular configuration. Adjacent to its lowerend, post 160 is coaxially formed with a further flange 162 that isspaced by a short axial distance from foot 160. The outer periphery offlange 162 is uniformly diametered. The bottom of foot 160 is flat andin a plane normally intersecting the longitudinal axis of post 154.

Foot 160 is elongated in the direction in which spacer portion 158 iselongated. Foot 160 and flange 162 cooperate to define two radiallyoutwardly opening, circumferentially spaced apart grooves 164 and 166 ondiametrically opposite sides of post 154. The edges 168 and 169 (FIG.8A) at the opposite ends of foot 160 are of segmental circular contour.

Posts 154 and 156 are substantially identical. Accordingly, likereference numerals suffixed by the letter a have been applied todesignate like portions of post I In its undeformed, relaxed condition,mounting member is symmetrical about a plane medially intersectingspacer portion 158 and containing the longitudinal axes of posts 154 and156. Mounting member 150 also is symmetrical about a plane that mediallyand perpendicularly intersects spacer portion 158.

Posts 154 anad 156 depend from spacer portion 158 adjacent to theopposite ends of spacer portions 158. The diameters of posts 154 and 156are somewhat smaller than the width of spacer portion 158.

As shown in FIGS. 2 and 10, mounting member 151 is identical to andinterchangeable with mounting member 150. Accordingly, like referencenumerals, but primed, have been applied to designate correspondingportions of mounting member 151.

Near the forward wall of housing 20, shells 60 and 62 are respectivelyformed with opposed, complementary cavities (FIG. 3) and 182 (FIG. 4)that open toward each other to interfittingly and slidably receivespacer portion 158. The housing wall surfaces defining the top andbottom of cavities 180 and 182 are flat and parallel. The wall definingthe bottom surface of cavity 180 is formed with an inwardly opening slot184 (FIGS. 3 and 11). The wall defining the bottom of cavity 182 issimilarly formed within an inwardly opening slot 186 (FIG. 4). Slots 184and 186 are complementary, opposed and open toward each other. Posts 154and 156 extend transversely through slots 184 and 186 respectively.

Cavities 180 and 182 terminate at the interface be tween shells 60 and62. Thus, the half of spacer portion 158 extending between one endthereof and a plane medially and normally intersecting spacer portion158 is received in cavity 180, while the remaining of half of spacerportion 158 is received in cavity 182. The dimension of the combinedcavity region defined by cavities 180 and 182 is just enough toaccommodate spacer portion 158 so that transverse movement of mountingmember 150 relative to housing 20 is precluded by abutment of theopposite ends of spacer portion 158 with the closed end wall regions ofcavities 180 anad 182. Movement of mounting member 150 in a directionextending longitudinally of housing 20 is precluded by abutment of theforwardly and rearwardly facing edges of spacer portion 158 withopposing wall surfaces of cavities 180 and 182.

The widths of slots 184 and 186 are equal and just large enough toaccommodate posts 154 and 156. As the result, the bottom wall portionsdefining cavities 180 and 182 seat against the downwardly facingmarginal edge regions of spacer portion 158 to provide a supporttherefor. Seating engagement of spacer portion 158 with the top andbottom wall portions defining cavities 180 and 182 prevent spacerportion 158 from flexing or twisting in cavities 180 and! 182.

In assembled relation with housing 20, spacer portion 158 extendstransversely of housing 20 closing adjacent to the front wall portion188 (FIG. 2) of housing 20. Spacer portion 158 is closely parallel toand spaced vertically above base 25. Cavities 180 and 182 locatemounting member 150 in such a manner that the lower ends of posts 154and 156 are positioned at the two front corners of base 25 as best shownin FIG. 13.

Adjacent to the rearwardly facing wall of housing 20, which is indicatedat 190 in FIG. 2, shells 60 and 62 are respectively formed with opposed,complementary cavities 192 (FIG; 3) and 194 (FIG. 4) that open towardeach other to slidably and interfittingly receive spacer portion 158 inthe same manner that spacer portion 158 is received in cavities 180 and182. The bottom walls defining cavities 192 and 194 are respectivelyformed with opposed, inwardly opening slots 196 (FIGS. 3 and 12) and 198(FIG. 4) that open toward each other.

The arrangement and construction of cavities 192 and 194 together withtheir slots 196 and 198 are substantially the same as cavities 180 and182 and slots 184 and 186. The assembly of spacer portion 158' incavities 192 and 194 is the same as that described for spacer portion158 and cavities 180 and 182. Cavity 192 receives the half of spacerportion 158' extending from one end thereof to a plane mediallyintersecting spacer portion 158, and the remaining half of spacerportion 158 is received in cavity 194. Posts 154' and 156' respectivelyextend transversely through slots 196 and 198 in the same manner asdescribed with regard to posts 154 and 156 and slots 184 and 186. Spacer158' is confined in cavities 192 and 194 in the same manner that spacer158 is confined in cavities 180 and 182.

Cavities 180, 182, 192 and 194 are formed in those regions of shells 60and 62 that define body portion 38. Cavities 180, 182, 192 and 194 areat a level below stator 30 as shown.

Cavities 192 and 194 locate mounting member 151 in such a manner thatthe lower ends of posts 154 and 156' are respectively at the tworearward corners of base 25 adjacent to rear wall 190. The lower ends ofposts 154, 156, 154' and 156 extend through and beyond the open bottomof housing 20.

Spacer portions 158 and 158 are each confined and trapped in placebetween interior surfaces of shells 60 p and 62 solely by separableseating surface engagement with the interior shell surfaces that definecavities 180, 182, 192 and 194. Spacer portions 158 and 158 are thustrapped in place between shells 60 and 62 when the shells are securedtogether to thereby secure mounting members 150 and 151 to housing 20 atthe upper ends of posts 154, 156, 154 and 156'. From this description itwill be appreciated that mounting members 150 and 151 are not secured tohousing 20 by fasteners and, instead, are trapped in place only byseparable seating surface engagement with interior surfaces of shells 60and 62.

In assembled relation, spacer portion 158 and 158' are spaced apart insubstantially coextensive, parallel relation. A plane containing eitherthe top surfaces of spacer portions 158 and 158 or the bottom surfacesof spacer portions 158 and 158 substantially normally intersects therotational axis of shaft 34. The rotational axis of shaft 34 issubstantially normal to base 25 and to the bottom flat surface of pad26.

Referring to FIG. 13, base plate 25, which may be molded from a suitableplastics material, is formed with four apertures or holes 200, 201, 202and 203. Apertures 200-203 are respectively disposed at the four cornersof base 25 and extend through base plate 25 along parallel spaced apartaxes.

Referring to FIGS. 8 and 9, the upper and lower end portions ofapertures 200 are circular and uniformly diametered. These upper andlower end portions of aperture 200 are respectively indicated at 206 and208 in FIG. 9 and are axially aligned. The mid-portion of aperture 200,which extends axially between end portions 206 and 208, is indicated at210 in FIGS. 8 and 9 and is non-circular as best shown in FIG. 8.Mid-portion 210 is defined in part by inwardly extending shoulder 212and 214 (FIG. 9) that provides mid-portion 210 with a generallyrectangular configuration that corresponds to foot 160. Shoulders 212and 214 are circum ferentially spaced apart on diametrically oppositesides of aperture 200.

From the foregoing it will be appreciated that aperture portions 206,208 and 210 respectively form axially aligned sockets 215 and 216 thatare axially separated by shoulders 212 and 214. Socket 215 is defined bythe smooth cylindrical peripheral wall of portion 206 and by shoulders212 and 214. Socket 216 is defined by the smooth cylindrical peripheralwall of portion 208 and by shoulders 212 and 214.

Apertures 2111-203 are the same as aperture'200. Accordingly likereference numerals suffixed by the letter a have been applied todesignate like portions of aperture 201, like reference numeralssuffixed by the letter b" have been applied to designate like portionsof apertures 202, and like reference numerals suffixed by the letter chave been applied to designate like portions of aperture 203.

In the assembled relation of mounting'members and 151 and base plate 25,the lower ends of posts 154, 156, 154 and 156 extend into apertures200-203 respectively. Foot 160 and flange 162 are respectively receivedin sockets 215 and 216, and the shoulders 212 and 214 of aperture 200extend into grooves 164 and 166 so that the two end portions of foot 160that extend in diametrically opposite directions beyond the adjacentregion of post 154 underlie and seat against the undersides of shoulders212 and 214. In this manner shoulders 212 and 214 are engaged by foot160 and flange 162 to interlock post 154 and base 25 and to therebydetachably secure or couple the lower end of post 154 to base plate 25.It will be appreciated that the coupling of the lower end of post 154 tobase plate 25 is only by separable seating surface engagement of flange162 and foot 160 with the base plate surfaces defining sockets 215 and216.

The fit of shoulders 212 and 214 in grooves 164 and 166 is snug. Theradii of edges 168 and 169 is closely equal to the diameter of socket216 so that foot 160 snugly seats in socket 216. Also, flange 162 snuglyand interfittingly seats in socket 215.

The manner in which the lower ends of posts 156, 154' and 156' aremounted in apertures 201-203 is the same as that just described for post154 and aperture 200. Thus, as shown in FIGS. 9 and 10, foot 160a seatsin socket 216a, flange 162a seats in socket 215a, shoulders 212a and2140 in grooves 166a and 168a, foot 160' seats in socket 216b, flange160 seats in socket 215b, shoulders 21212 and 214b seat in grooves 166'and 168', foot 160a seats in socket 216e, flange 162a seats in socket215C, and shoulders 212e and 214e seat in grooves 166a and 168a.

From the foregoing description it will be appreciated that the lowerends of posts 154, 156, 154 and 156 are detachably coupled to base plate25 only by separable seating surface engagement with base plate 25.Mounting members 150 and 151 are therefore not secured to base plate 25by fasteners of any kind.

From FIGS. 8, 9, 10 and 13, it will be observed that the generallyrectangular mid-portions 210, 210a, 21Gb and 2111c of apertures 200203are each elongated in a direction extending longitudinally of the sanderas indicated by axis A-A in FIG. 8, whereas feet 160, 160a, 160' and160a are each elongated along an axis B-B (See FIG. 8) that extendstransversely of the sander and at right angles to the elongation axesA-A when mounting members 150 and 151 are relaxed and undistorted.

To couple post 154 with base plate 25, foot 160 is turned through anangle of approximately 90 by torsionally deflecting post 154 (See FIG.14) and/or by flexing spacer portion 158 to align foot 160 withmidportion 211) in such a manner that its axis of elongation B--Bextends in the same direction as is and parallel to axis A-A. Foot 160then may be pushed axially through mid portion 210 to seat in socket216. Member 150 is then relaxed to its undeformed condition to rotatefoot 160 to a locking position where it underlies shoulders 212 and 214and where axis A-A is essentially at right angles to axis B-B.

Post 156, 154 and 156 are coupled to base plate 25 in the same mannerjust described for post 154. Posts 154, 156, 154' and 156 flex orresiliently yield to allow orbital or oscillatory motion of pad assembly24 relative to housing 20.

To detach pad assembly 24 from mounting members 150 and 151, themounting posts and/or spacer portions are deformed to turn each couplingfoot to a position where its axis AA is parallel to axis 8-8. The footof each post may then be pulled out of its associated aperture todisconnect it from base plate 25.

From the foregoing description, it will be appreciated that foot 160 andsocket 216 provide a bayonet like connection for detachably securing thelower end of post 154 to base plate 25. Foot 160 is turnable orrotatable in socket 216 between and a locking position where its endportions underlie shoulders 212 and 214 and an unlocking position whereit clears shoulders 212 and 214. Likewise, foot 160a and socket 216aprovide a bayonet like connection for detachably securing the lower endof post 156 to base plate 25, foot 160 and socket 216b provide a bayonetlike connection for detachably securing post 154 to base plate 25, andfoot 160a and socket 216c provide a bayonet-like connection fordetachably securing post 156 to base plate 25. Each of the feet 1600,160 and 160a is rotatable in its socket between locking and unlockingpositions in the manner just described for foot 160.

Because of the manner in which members 150 and 151 are secured to orinterlocked with housing and base and because no fasteners are requiredfor securing posts 154, 156, 154' and 156 to housing 20 or base plate25, the assembly and disassembly of parts for yieldable supporting padassembly 23 from housing 20 is simplified, easy and quick. Lubricantmaybe applied to members 150 and 151 to further ease the assembly ofmembers 150 and 151 with shells 60 and 62 and base plate 25.

A longitudinal plane containing the axis of shaft 34 and normallyintersecting pad assembly 24 medially and normally intersects spacerportions 158 and 158. Posts 154, 154, 156 and 156 are symmetricallocated relative to this plane, two being located on one side of theplane and two being located on the opposite side of the plane. Thisplane also passes substantially through the interface between shells 60and 62.

It will be appreciated that the present invention thus far described maybe utilized in conjunction with other abrading machines in which motionof the pad assembly or base plate is other than orbital.

As shown in FIGS. 1, 2 and 8, the sander of this invention is providedwith a pair of sandpaper or abrading paper holders or clamping members230 and 232. Holders 230 and 232 are pivotally mounted directly on base25 at the front and rear ends of the sander for clamping the sandpaperor abrading paper in place on pad assembly 24.

Holder 230 is a one piece member and is formed, as by stamping, from aflat-sided metal plate. As shown in FIGS. 1, 2, 8 and 15-17, holder 230comprises a flatsided, generally rectangular body or clamping portion234 and a pair of parallel, flat-sided, spaced apart earlike pivotportions 235 and 236. Clamping portion 234 is integral with and extendsbetween pivot portions 235 and 236. Pivot portions 235 and 236 extendfrom the opposite side edges of clamping portion 234 and are bent backto extend at right angles from clamping portion 234.

.The bottom edge of each of the pivot portions 235 and 236 is formedwith an arcuate, downwardly opening notch 238. Base plate 25 isintegrally formed with a pair of upwardly extending, spaced apartbearing portions 240 and 242 (see FIG. 13) that respectively seat in andextend through the notches 238 of pivot portions 235 and 236.

Pivot portions 235 and 236 are coextensive and are provided withsubstantially identical configurations. The longitudinal axes of thenotches 238 in portions 235 and 236 are axially aligned.

Bearing portions 240 and 242 have corresponding configurations, areadjacent to the front edgeof base plate 25, and protrude upwardly fromthe top flat surface region of the base plate. As shown in FIGS. 18 and19, the upper ends of bearing portions 240 and 242 are smoothly curvedto interfit with notches 238.

Preferably, the curved ends of bearing portion 240 and 242 that seatagainst the arcuate edges of notches 236 and substantially uniformlydiametered, and the arcuate edges of notches 238 that seat on the curvedends of bearing portions 240 and 242 are also substantially uniformlydiametered to provide for smooth pivotal motion of holder 230 about theaxially aligned pivot axes of the curved end regions of bearing portions240 and 242.

At the mouth of the notch 238 in pivot portion 235, portion 235terminates in a finger 244 (see FIGS. 17 and 18) that curves back toardclamping portion 234 and that extends into a slot or narrow hole 246 inbearing portion 240. Pivot portion 236 terminates in a similar finger248 (FIG. 19) at the mouth of its notch 238, and finger 248 similarlyextends into a slot or narrow hole 250 in bearing portion 242. The endsof fingers 244 and 248 delimit the mouths of the notches 238 in pivotportions 235 and 236.

As shown in FIGS. 2, 15 and 17, the bottom of body portion 234terminates a straight-edged paper clamp ing lip 252 that is bent backtowards fingers 244 and 248. Lip 252 extends parallel to the pivot axisof holder 230 and is spaced from fingers 244 and 248 so that the end oflip 252 delimits the mouths of notches 238 in pivot portions 235 and236. Hence, the mouth of the notch 238 in pivot portion 235 is delimitedby finger 244 and lip 252, and the mouth of notch 238 in pivot portion236 is delimited by finger 248 and lip 252.

The spacing between the end of lip 252 and the end of each of thefingers 244 and 248 is less than the widths of bearing portions 240 and242. Only the thickness or height of each of the bearing portions 240and 242 extending vertically between its upper end and the upper end ofits slot 246, 250 is less than the spacing between lip 252 and each ofthe fingers 244 and 248. With this construction, it is necessary topivot or rotate holder 230 clockwise (as viewed from FIG. 2) to theposition shown in FIG. where body portion 234 is approximately or almostparallel with and overlies base plate in order to disengage holder 230from base plate 25. When body portion 234 is approximately or almostparallel with base plate 25, the mouths of notches 238 will faceforwardly to receive the bearing portion regions extending between slots246 and 250 and the upper ends of bearing portions 240 and 242, thuspermitting disengagement of holder 230 by moving it relative to baseplate 25 and toward the rotational axis of motor 22.

When holder 230 is in any other position where body portion 234 is notapproximately or almost parallel to base plate 25, it cannot bedisengaged from bearing portions 240 and 242 because fingers 244 and 248will butt against the upper wall regions of slots 246 and 250.

In order to rotate holder 230 to its position where it is disengageablefrom bearing portions 240 and 242 it is first necessary to removemounting member 150 and a leaf spring 254. Spring 254 biases holder 230in a counterclockwise direction (as viewed from FIG. 2) to itsillustrated, upright paper-clamping position where body portion 234 isclosely perpendicular to base plate 25. In this clamping position,holder 230 is angularly spaced from its position where it isdisengageable from bearing portions 240 and 242 by a magnitudeapproaching 90.

As viewed from FIG. 2, counterclockwise rotation of holder 230 islimited by abutment of lip 252 with the flat vertical front surface of astraight ridge portion 256. Ridge portion 256 is integral with baseplate 25 and extends across the front of base plate 25 at right anglesto the straight parallel sides of the base plate. Bearing portions 240and 242 protrude upwardly from ridge portion 256. I

At its forward end, base plate 25 terminates in a ledge portion 258.Ledge portion 258 projects forwardly beyond ridge portion 256 and isperpendicular to ridge portion 256 to define a stepped region over whichthe sandpaper is folded. In particular, the forward end of the sandpapersheet 28 is folded up over the forward edge of ledge portion 258, thenback over the horizontal surface of ledge portion 258 and finally upbetween lip 252 and the vertical front face of ridge portion 256. Theend of the sandpaper sheet is clamped between lip 252 and the front faceof ledge portion 256, and spring 256 biases holder 230 to its clampingposition where it seats against the sandpaper sheet.

As shown in FIG. 2, the end portion of spring 254/remote from holder 230is separably seated in shallow, interfitting, upwardly opening recess260 that is formed in the top surface of base plate 25. The region ofspring 254 between recess 260 and its end that seats against holder 230is flexed upwardly from base plate 25 as shown.

The end of spring 254 remote from recess 260 seats against an arcuatetab 262 which is integral with the body portion 234 of holder 230. Tab262 is formed in body portion 234 by parallel spaced apart cutsextending from the upper edge of body portion 234. The curvature of tab262 provides for the application of the spring force in such a directionthat holder 230 is biased in a counterclockwise direction (as viewedfrom FIG. 2) to its paper clamping position. A bridge portion 263, whichis integral with base plate 25, crosses over spring 254 at the forwardend of recess 260 to keep spring 254 from snaping out of the recess.

To remove an old sheet of sandpaper or to mount a new sheet on padassembly 24, holder 230 is rotated in a clockwise direction as viewedfrom FIG. 2 to move lip 252 away from ridge portion 256. In thispaperunclamping position, holder 230 is still angularly spaced by asignificant magnitude from its position where it is disengageable frombearing portions 240 and 242. Thus, the operative clamping andunclamping positions of holder 230 are angularly spaced by significantdistances from the position where holder 230 is disengageable from baseplate 25. Furthermore, holder 230 cannot be pivoted back towards motor22 and to its position where it is disengageable from base plate 25without first removing mounting member 150. It will be appreciated thatthe unclamping position of holder 230 is angularly spaced between itsclamping position and its position where it is disengageable from baseplate 25.

A pair of ears (see FIG. 13), which are integral with bearing portions240 and 242, extend between and are abuttable against pivot portions 235and 236 to confine holder 230 against motion along its pivot axis.

The construction of holder 232 is the same as the construction of holder230. Accordingly, like reference numerals suffixed by the letter a havebeen applied to designate corresponding portions of holder 232. Holders230 and 232 are interchangeable. Holder 232 is pivotally mounteddirectly on the base plate 25 in the same manner just described from forholder 230. Holder 232 is at the rearward end of base plate 25 forclamping the rear edge portion of the sandpaper sheet 28. The base plateconstruction for mounting holder 232 and for clamping the rearward edgeof sheet 28 is the same as that just described for mounting holder 230and for clamping the forward edge of sheet 28. Accord ingly, likereference numerals suffixed by the letter a have been applied todesignate the corresponding base plate portions that are associated withholder 232. These portions include bearing portions 240a and 242a whichcorrespond to bearing portion 240 and 242, ridge portion 256a whichcorresponds to ridge portion 256 and ledge portion 258a whichcorresponds to ledge portion 258.

A spring 254a biases holder 232 in a clockwise direction (as viewed fromFIG. 2) to its paper clamping position. Spring 254a is of the sameconstruction and is interchangeable with spring 254. The base plateconstruction for mounting spring 254a is the same as that described forspring 254. This includes the shallow recess 260a and the bridgingportion 263a which respectively corresponds to recess 260 and bridgingportion 263. Ridge portions 256 and 256a are parallel as shown.

Base plate is symmetrical about a plane containing the axis of socket110 and perpendicularly intersecting the base plate in parallel relationwith ridge portions 256 and 256a.

From the foregoing it will be appreciated that holder 23b is hingeddirectly on base plate 25 by engagement of pivot portions 235 and 236with bearing portions 240 and 242. Similarly, holder 232 is hingeddirectly on base plate 25 by engagement of pivot portions 235a and 236awith bearing portions 240a and 242a. As a result, the need for separatepivot pins or the like is eliminated with the construction of thisinvention. Holders 230 and 232 are pivotable about parallel spaced apartaxes.

Holder 232 is disengageable from bearing portions 240a and 242a in thesame manner as described for holder 230. Mounting member 151 must firstbe removed in order to permit holder 232 to be pivoted to itsdisengaging position where body portion 234a is approximately or almostparallel with base plate 25.

As shown in FIG. 2, the rearward end of sandpaper sheet 28 is foldedback over ledge 248a and then up between ridge portion 246a and lip252a.

The sander of this invention may be assembled and disassembled indifferent ways. One way of assembly is to mount holders 230 and 232 andsprings 254 and 254a in place on base plate 25. The sub-assembly ofmotor 22 and mechanism 23 may be mounted on base plate 25 before orafter the mounting of holders 230 and 232. Next, mounting members 150and 151 are mounted on base plate 25, and finally shells 60 and 62 aremounted in place and fastened together by screws 63.

Spacer portions I58 and 158' are sufficiently thin to enable posts 154,156, 154 and 156 to be rotated about their longitudinal axes by flexingor deforming spacer portions 158 and 158. Thus, when shells 60 and 62are disassembled from mounting members 150 and 151, coupling feet 160,160a, 160 and 160a may be turned or rotated to either their coupling oruncoupling positions simply by flexing or deforming spacer portions 153and 158'.

Holders 230 and 232 are rigid one-piece members and do not flex as theyare pivoted between their clamping and unclamping positions.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a handmanipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate and providing a backing fora sheet of sandpaper, means comprising a motor supported by said housingfor imparting motion to the assembly of said base plate and said pad, aplurality of posts carried by said housing for suspending said baseplate from said housing, said posts being formed from elasticallydeformable material to permit motion of said base plate relative to saidhousing by operation of said motor, and cooperating means on said baseplate and the lower end of each of said posts for providing a detachablebayonet like connection between said base plate and the lower end ofeach post.

2. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate to provide a backing for asheet of sandpaper, means comprising a motor supported by said housingfor imparting motion to the assembly of said base plate and said pad, aplurality of one-piece mounting members carried by said housing forsupporting said base plate from said housing, said mounting membersbeing formed from elastically deformable material to permit motion ofsaid assembly relative to said housing by operation of said motor, eachof said mounting members comprising a pair of spaced apart posts and aspacer portion integrally joined to said posts at corresponding endsthereof, and cooperating means integral with said base plate and each ofsaid posts at the end thereof opposite from the spacer portion forproviding a detachable bayonet-like connection between said base plateand each of said posts.

3. The handmanipulatable, poweroperated sanding machine defined in claim2 wherein said housing comprises a pair of separately formed shells, andwherein means are provided for securing said shells together, saidspacer portion of each mounting member being received in cavities formedin said shells and being trapped in place between interior surfaces ofsaid shells.

4. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate to provide a backing for asheet of sandpa per, means comprising a motor supported by said housingfor imparting motion to the assembly of said base plate and said pad, atleast one mounting member carried by said housing for supporting theassembly of said base plate and said pad from said housing, saidmounting member being formed from elastically deformable material topermit motion of said assembly relative to said housing by operation ofsaid motor, said mounting member having a pair of posts and a spacerportion extending between and joined to said posts at corresponding endsthereof, a coupling portion positioned on the end of each post oppositefrom said spacer portion, a coupling structure for each post, eachcoupling structure being positioned on said base plate for engagementwith an associated one of said coupling portions to de tachably couplesaid base plate to said posts, each coupling portion being disengageablefrom its associated coupling structure by rotational deformation of saidmounting member to uncouple said base plate from said posts.

5. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate to provide a backing for asheet of sandpaper, means comprising a motor in said housing forimparting motion to the assembly of said base plate and said pad, firstand second mounting members carried by said housing for supporting saidassembly from said housing and formed from elastically deformablematerial to permit motion of said assembly relative to said housing byoperation of said motor, each of said mounting members comprising a pairof posts, a spacer portion extending between and integrally joined tosaid posts at corresponding ends thereof, and a coupling portionintegral with each post, said base plate being integrally formed with acoupling structure for each of said posts, each coupling structure beingpositioned to engage an associated one of said coupling portions todetachably couple said base plate to said posts, and each couplingportion being disengageable from its associated coupling structure byrotational deformation of its associated mounting member for uncouplingsaid base plate from said posts.

6. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate to provide a backing for asheet of sandpaper, means comprising a motor supported by said housingfor imparting motion to the assembly of said base plate and said pad,first and second mounting members carried by said housing for supportingsaid assembly from said housing and formed from elastically deformablematerial to permit motion of said assembly relative to said housing byoperation of said motor, each of said mounting members comprising a pairof posts, a spacer portion extending between and integrally joined tosaid posts at corresponding ends thereof, and a coupling portionintegral with each post at the end thereof opposite from its associatedspacer portion, said base plate being integrally formed with a couplingstructure for each of said posts, each coupling structure beingpositioned to engage an associated one of said coupling portions todetachably couple said base plate to said posts, and each couplingportion being disengageable from its associated coupling structure bytorsional deflection of its associated post or by flexing its associatedspacer portion to uncouple said base plate from said posts.

7. The hand-manipulatable, power-operated sanding machine defined inclaim 6 wherein each coupling portion comprises a coupling flange thatis rotatable from a coupling position to an uncoupling position that isangularly spaced from said coupling position by torsion ally deflectingits associated post or by flexing its associated spacer portion, andwherein each coupling structure comprises a pair of shoulders positionedin a hole that is formed in said base plate for each coupling flange,said coupling flange being insertable into its associated hol-e beyondsaid shoulders when in said uncoupling position, and said couplingflange being engaged with the undersides of said shoulders when it isrotated within its associated hole to said coupling position.

8. The hand-manipulatable, power-operated sanding machine defined inclaim 6 wherein said housing is longitudinally divided into a pair ofseparately formed shells, wherein means are provided for securing saidshells together, wherein the spacer portion of each of said mountingmembers is trapped between said shells, and wherein said shells havewall portions that engage the spacer portion of each of said mountingmembers to prevent flexure of said spacer portions in the assembledrelation of said shells with said mounting members.

9. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate and providing a backing fora sheet of sandpaper, means comprising a motor in said housing forimparting motion to the assembly of said base plate and said pad, aplurality of torsionally deflectible posts of elastically deformablematerial supported at corresponding ends from said housing, each of saidposts being integrally formed with a coupling portion, each couplingportion being rotatable from a coupling position to an uncouplingposition that is angularly spaced from said coupling position bytorsional deflection of its associated post, said base plate beingintegrally formed with a coupling structure for each of the couplingportions, each coupling portion being engaged with its associatedcoupling structure when in said coupling position to couple said poststo said base plate, and each coupling portion being disengaged from itsassociated coupling structure when in said uncoupling position touncouple said posts from said base plate.

10. In a hand-manipulatable, power-operated sanding machine, a housinghaving a body portion, a pad assembly providing a backing for a sheet ofsandpaper, a plurality of one-piece members of elastically deformablematerial suspending said pad assembly from said body portion to permitmotion of said pad assembly relative to said housing, means comprising amotor in said housing for imparting motion to said pad assembly, atleast said body portion of said housing being divided longitudinallyinto a pair of separately formed shells, and means securing said shellstogether, corresponding ends of said one-piece members being trappedbetween said shells and being held in place only by separable seatingsurface engagement with interior surfaces of said shells.

11. The hand-manipulatable, power-operated sanding machine defined inclaim 10 wherein each of said one-piece members comprises a pair ofspaced apart posts having their upper ends received in said body portionand a spacer portion integrally joined to the upper ends of said postswithin said body portion, the lower ends of said posts being secured toa part of said pad assembly.

12. In a hand-manipulatable, power-operated sanding machine, a housinghaving a body portion, a pad assembly providing a backing for a sheet ofsandpaper, first and second mounting members of elastically de forrnablematerial for suspending said pad assembly from said housing andpermitting relative motion be tween said pad assembly and said housing,each of said mounting members comprising a pair of posts connected atcorresponding ends to said pad assembly and a spacer portion integrallyjoined to and extending between said posts at the opposite ends thereof,at least said body portion of said housing being longitudinally dividedinto a pair of separately formed shells having a first pair of inwardlyopening cavities and a second pair of inwardly opening cavities spacedfrom said first pair of cavities, and means securing said shellstogether, the spacer portion of said first member being received in thecavities of said first pair of cavities and being held in place only byseparable seating surface engagement with interior cavity-definingsurfaces of said shells, and said spacer portion of said second memberbeing received in the cavities of said second pair of cavities and beingheld in place only by separable seating surface engagement with interiorcavity-defining surfaces of said shells.

13. In a hand manipulatable, power operated sanding machine, a baseplate of rectangular configuration, a pad secured to said base plate toprovide a backing for a sheet of sandpaper, drive means for impartingmotion to the assembly of said base plate and said pad, a pair ofsandpaper holders, said base plate being integrally formed with at leastone bearing portion for each of said sandpaper holders, and eachsandpaper holder being pivotally mounted directly on its associatedbearing said holders to their sandpaper-clamping positions, said springmeans comprising a flat-sided leaf spring for each of said holder, eachleaf springbeing seated at one end thereof in a shallow recess in saidbase plate, and the other end of each leaf spring being seated against aportion of its associated holder.

l= l l k

1. In a hand-manipulatable, power-operated sanding machine, a housing, abase plate, a pad secured to said base plate and providing a backing fora sheet of sandpaper, means comprising a motor supported by said housingfor imparting motion to the assembly of said base plate and said pad, aplurality of posts carried by said housing for suspending said baseplate from said housing, said posts being formed from elasticallydeformable material to permit motion of said base plate relative to saidhousing by operation of said motor, and cooperating means on said baseplate and the lower end of each of said posts for providing a detachablebayonet like connection between said base plate and the lower end ofeach post.
 2. In a hand-manipulatable, power-operated sanding machine, ahousing, a base plate, a pad secured to said base plate to provide abacking for a sheet of sandpaper, means comprising a motor supported bysaid housing for imparting motion to the assembly of said base plate andsaid pad, a plurality of one-piece mounting members carried by saidhousing for supporting said base plate from said housing, said mountingmembers being formed from elastically deformable material to permitmotion of said assembly relative to said housing by operation of saidmotor, each of said mounting members comprising a pair of spaced apartposts and a spacer portion integrally joined to said posts atcorresponding ends thereof, and cooperating means integral with saidbase plate and each of said posts at the end thereof opposite from thespacer portion for providing a detachable bayonet-like connectionbetween said base plate and each of said posts.
 3. Thehand-manipulatable, power-operated sanding machine defined in claim 2wherein said housing comprises a pair of separately formed shells, andwherein means are provided for securing said shells together, saidspacer portion of each mounting member being received in cavities formedin said shells and being trapped in place between interior surfaces ofsaid shells.
 4. In a hand-manipulatable, power-operated sanding machine,a housing, a base plate, a pad secured to said base plate to provide abacking for a sheet of sandpaper, means comprising a motor supported bysaid housing for imparting motion to the assembly of said base plate andsaid pad, at least one mounting member carried by said housing forsupporting the assembly of said base plate and said pad from saidhousing, said mounting member being formed from elastically deformablematerial to permit motion of said assembly relative to said housing byoperation of said motor, said mounting member having a pair of posts anda spacer portion extending between and joined to said posts atcorresponding ends thereof, a coupling portioN positioned on the end ofeach post opposite from said spacer portion, a coupling structure foreach post, each coupling structure being positioned on said base platefor engagement with an associated one of said coupling portions todetachably couple said base plate to said posts, each coupling portionbeing disengageable from its associated coupling structure by rotationaldeformation of said mounting member to uncouple said base plate fromsaid posts.
 5. In a hand-manipulatable, power-operated sanding machine,a housing, a base plate, a pad secured to said base plate to provide abacking for a sheet of sandpaper, means comprising a motor in saidhousing for imparting motion to the assembly of said base plate and saidpad, first and second mounting members carried by said housing forsupporting said assembly from said housing and formed from elasticallydeformable material to permit motion of said assembly relative to saidhousing by operation of said motor, each of said mounting memberscomprising a pair of posts, a spacer portion extending between andintegrally joined to said posts at corresponding ends thereof, and acoupling portion integral with each post, said base plate beingintegrally formed with a coupling structure for each of said posts, eachcoupling structure being positioned to engage an associated one of saidcoupling portions to detachably couple said base plate to said posts,and each coupling portion being disengageable from its associatedcoupling structure by rotational deformation of its associated mountingmember for uncoupling said base plate from said posts.
 6. In ahand-manipulatable, power-operated sanding machine, a housing, a baseplate, a pad secured to said base plate to provide a backing for a sheetof sandpaper, means comprising a motor supported by said housing forimparting motion to the assembly of said base plate and said pad, firstand second mounting members carried by said housing for supporting saidassembly from said housing and formed from elastically deformablematerial to permit motion of said assembly relative to said housing byoperation of said motor, each of said mounting members comprising a pairof posts, a spacer portion extending between and integrally joined tosaid posts at corresponding ends thereof, and a coupling portionintegral with each post at the end thereof opposite from its associatedspacer portion, said base plate being integrally formed with a couplingstructure for each of said posts, each coupling structure beingpositioned to engage an associated one of said coupling portions todetachably couple said base plate to said posts, and each couplingportion being disengageable from its associated coupling structure bytorsional deflection of its associated post or by flexing its associatedspacer portion to uncouple said base plate from said posts.
 7. Thehand-manipulatable, power-operated sanding machine defined in claim 6wherein each coupling portion comprises a coupling flange that isrotatable from a coupling position to an uncoupling position that isangularly spaced from said coupling position by torsionally deflectingits associated post or by flexing its associated spacer portion, andwherein each coupling structure comprises a pair of shoulders positionedin a hole that is formed in said base plate for each coupling flange,said coupling flange being insertable into its associated hole beyondsaid shoulders when in said uncoupling position, and said couplingflange being engaged with the undersides of said shoulders when it isrotated within its associated hole to said coupling position.
 8. Thehand-manipulatable, power-operated sanding machine defined in claim 6wherein said housing is longitudinally divided into a pair of separatelyformed shells, wherein means are provided for securing said shellstogether, wherein the spacer portion of each of said mounting members istrapped between said shells, and wherein said shells have wall portionsthat engage the spacer portion of each of Said mounting members toprevent flexure of said spacer portions in the assembled relation ofsaid shells with said mounting members.
 9. In a hand-manipulatable,power-operated sanding machine, a housing, a base plate, a pad securedto said base plate and providing a backing for a sheet of sandpaper,means comprising a motor in said housing for imparting motion to theassembly of said base plate and said pad, a plurality of torsionallydeflectible posts of elastically deformable material supported atcorresponding ends from said housing, each of said posts beingintegrally formed with a coupling portion, each coupling portion beingrotatable from a coupling position to an uncoupling position that isangularly spaced from said coupling position by torsional deflection ofits associated post, said base plate being integrally formed with acoupling structure for each of the coupling portions, each couplingportion being engaged with its associated coupling structure when insaid coupling position to couple said posts to said base plate, and eachcoupling portion being disengaged from its associated coupling structurewhen in said uncoupling position to uncouple said posts from said baseplate.
 10. In a hand-manipulatable, power-operated sanding machine, ahousing having a body portion, a pad assembly providing a backing for asheet of sandpaper, a plurality of one-piece members of elasticallydeformable material suspending said pad assembly from said body portionto permit motion of said pad assembly relative to said housing, meanscomprising a motor in said housing for imparting motion to said padassembly, at least said body portion of said housing being dividedlongitudinally into a pair of separately formed shells, and meanssecuring said shells together, corresponding ends of said one-piecemembers being trapped between said shells and being held in place onlyby separable seating surface engagement with interior surfaces of saidshells.
 11. The hand-manipulatable, power-operated sanding machinedefined in claim 10 wherein each of said one-piece members comprises apair of spaced apart posts having their upper ends received in said bodyportion and a spacer portion integrally joined to the upper ends of saidposts within said body portion, the lower ends of said posts beingsecured to a part of said pad assembly.
 12. In a hand-manipulatable,power-operated sanding machine, a housing having a body portion, a padassembly providing a backing for a sheet of sandpaper, first and secondmounting members of elastically deformable material for suspending saidpad assembly from said housing and permitting relative motion betweensaid pad assembly and said housing, each of said mounting memberscomprising a pair of posts connected at corresponding ends to said padassembly and a spacer portion integrally joined to and extending betweensaid posts at the opposite ends thereof, at least said body portion ofsaid housing being longitudinally divided into a pair of separatelyformed shells having a first pair of inwardly opening cavities and asecond pair of inwardly opening cavities spaced from said first pair ofcavities, and means securing said shells together, the spacer portion ofsaid first member being received in the cavities of said first pair ofcavities and being held in place only by separable seating surfaceengagement with interior cavity-defining surfaces of said shells, andsaid spacer portion of said second member being received in the cavitiesof said second pair of cavities and being held in place only byseparable seating surface engagement with interior cavity-definingsurfaces of said shells.
 13. In a hand manipulatable, power operatedsanding machine, a base plate of rectangular configuration, a padsecured to said base plate to provide a backing for a sheet ofsandpaper, drive means for imparting motion to the assembly of said baseplate and said pad, a pair of sandpaper holders, said base plate beingintegrally formed with at least one beaRing portion for each of saidsandpaper holders, and each sandpaper holder being pivotally mounteddirectly on its associated bearing portion and having means integralwith said bearing portions and said holders for preventing each holderfrom being disengaged from its associated bearing portions except whensaid holders are pivoted to pre-selected positions.
 14. Thehand-manipulatable, power-operated sanding machine of claim 13 havingspring means for biasing said holders to their sandpaper-clampingpositions, said spring means comprising a flat-sided leaf spring foreach of said holder, each leaf spring being seated at one end thereof ina shallow recess in said base plate, and the other end of each leafspring being seated against a portion of its associated holder.